I always thought self-deprecation was the odd remark you made when someone over describes you: Ask X, they are the crossword expert' and you reply with a self-deprecatory remark about being good at saying cross words.
Having said that, I have long believed that self-esteem is a very dangerous concept, esteem is something earned from others who recognise what in you is admirable, self-esteem is narcissim, convincing yourself that you are wonderful regardless of the evidence and it can be very damaging when this belief is undermined by academic or work failure.
What we should be teaching our children and young people is self-respect and self confidence and the second comes from the first. They should know that regardless of their talents and abilities they have a right to be treated justly, fairly and equally and that their bodies are their own and no one but they should decide how they look and the limits to body access. If children know that they will have the confidence to accept that nobody is good at everything, that failure is part and parcel of life and we have to be able to accept we have limitations.
Which brings me back to the article. Bragging, boasting, singing your own praises, is unpleasant and puts people off but there is nothing to stop somebody talking about what they have done and how effective it was in the appropriate place to the appropriate person. When DH, an engineering project manager, was working he was constantly exasperated by young graduates claiming they had played a significant management role in every project they had ever worked on. As he said if they were to be believed the Channel Tunnel was built by 50,000 managers and the tea boy.
What medical conditions seem more common now than when you were growing up?

